1. Technical Field
The present invention relates generally to dynamic circuits and in particular to a method and apparatus for detecting a leakage current from a dynamic circuit. Still more particularly, the present invention provides a method and apparatus for providing a nominal keeper circuit size for a dynamic circuit based on a detected leakage current of the dynamic circuit.
2. Description of Related Art
Conventional dynamic circuits have many advantages over static circuit counterparts. However, a disadvantage of a dynamic circuit is the necessity to hold a logic-low voltage, e.g., a “0” voltage, output during an evaluate cycle. Leakage currents often make it difficult for a 0-level output to be consistently maintained on the circuit output. Often a keeper structure is added to the circuit for maintaining the 0 voltage.
It is difficult to guarantee proper operation of a dynamic circuit while at the same time guaranteeing performance in the case where technology applications are not easy to determine prior to circuit design. A keeper structure sized too large for a particular circuit application increases the difficulty for ensuring a proper evaluate cycle. A keeper structure sized too small facilitates an evaluation cycle of the dynamic circuit but may disadvantageously fail to hold logic low pre-charge values of the dynamic circuit thus failing to guarantee proper logic operation of the circuit.
Thus, it would be advantageous to provide a method and apparatus to determine the current leakage for a particular circuit application and activate a nominal keeper structure needed to guarantee proper logic operation of the dynamic circuit.